Modified resin composition



' Patented Mar. 1, 1938 PATENT OFFICE 2,109,573 7 MODIFIED RESIN OOIHPOSITION Barnard M. Marks, Arlington, N. 1., assignor, by

mesne assignments, to E. 1. du Pont de Nemours & Company, Wilmington, DcL, a corporation of Delaware No Drawing. Application July 15, 1936, Serial No. 90,729

3 Claims.

polyvinyl acetal resin may. be formed by a one stage process in'which hydrolysis of the polyvinyl ester and reaction of the polyvinyl alcohol thus formed,-with an aldehyde, are carried out substantially simultaneously. Alternatively, thetwo reactions may be carried out in two separate stages. The hydrolysis of the polyvinyl ester may not be complete so that some acetyl radicals still persist in the polyvinyl acetal resin formed,

affecting the properties of the resin to some extent. Detailed disclosure of these polyvinyl acetal resins and their preparation is found in United States Patent 2,036,092.

An object of the present invention is to provide new modified compositions comprising polyvinyl acetal resins and, as plasticizers or high boiling solvents therefor, esters which are highly compatible with the ordinary ingredients used in the coating, film, and plastic arts, which esters have low vapor pressures and otherwise acceptable properties.- A further-object is to provide new polyvinyl acetal compositions. 'Other ob- Jects will be apparent fromthe description of the invention given hereinafter.

The above objects are accomplished according to the present invention by employing, as a modifier in polyvinyl acetal resin compositions,

an ether derivative of anester of a hydroxy monocarboxylic acid represented by the formula RiORiCOQR3, where R1 is an aryl or aralkvl radicalv containing not more than carbon atoms, R: isa divalent hydrocarbon radical containing not more than 1'! carbon atoms, and Rs the sodium derivative with a halide of the desired hydrocarbon radical represented by R1 in the above formula. Also the halogenated ester such as ethylalphaor beta-chlorpropionate. orthe like, may be reacted with the sodium derivative of the desired alcohol, or phenol.

Among the ether derivatives herein used as modifiers, benzyl ether of ethyl lactate, having a boilingpoint of approximately 235C. at 760 mm., benzyl ether of ethyl glycollate, boiling point 155 C. at 21 mm., and phenyl ether of ethoxy butyrate, boiling point 190 C. at 23 mm., are particularly well adapted as plasticizers for the polyvinyl acetal resins. All of these ether derivatives are suitable as modifying agents for polyvinyl acetal resins. f

In the formula representing these ether derivatives R1ORzCOORs, R1 is an aryl or aralkyl radical containing not more than 10 carbon atoms. Specific examples of such radicals are phenyl, tolyl, xylyl, chlorophenyl, chlorotolyl. benzyl, and phenylethyl-radicals. R: is a divalent hydrocarbon radical containing not more than 17 carbon atoms, examples of which are CH2- to CuH:4, including-the various iso and branched chain analogues, as 1 and R3 is a monovalent radical derived from a hydroxyl compound of the class consisting of .alkyls and phenyl, benzyl, phenylethyLtolyl radicals, and the like.

The ether derivatives coming within the pres-' ent invention are only those wherein the sum of the carbon atoms in R2' and R: do not exceed 25. For example, when R: isCuH:+-,

Ra'must not be higher than CsHn-'; or where R: is C1sH:s--, R: must not'be higher than C1Hn-, and the highest molecularlweight compound would be: CmHiaOCvHuCOOCuHu or,

CioHiaOCi'lHuCOOCsHm.

- Compounds having a higher molecular weight than the above are not practically operative in the presentinvention because of their waxy nature and lack of compatibility withthe. polyvinyl acetal resins. Furthermore, it is preferred that the sum of the carbon atoms of R: and R;

should not exceed 12.

All of the ether derivatives herein included are high boiling substantially colorless liquids or substantially white solids compatible with the usual solvents, diluents, and the like; used in the coating and plastics arts. Further, they are prac-' tically insoluble in water, and relatively stable toward hydrolysis.

In making the polyvinyl acetal resin compositions employing the ether derivatives of the present invention, the compositions, whether plastics or solutions, may be made up in any of the usual ways of the art, tlie introduction or the particular modifiers herein described not necessitating departures from the standard practice- Thus, the modifiers may be worked with the polyvinyl acetal resin in a mixer with a'small amount of solvent or thepolyvinyl acetal resin and modifier, either initially or after being made into a plastic, may be dissolved in a large amount of solvent to give a solution, or dope", and the like, the modifier being a colloiding agent for the resin.

In working up plastics after mixing of the ingredients, the plastic may be filtered, vacuum mixed, cake pressed, sheeted, and seasoned in accordance .with' standard practice. Likewise, dcpes may be used in casting films and for coating compositions while the plastics may be used in molding compositions, as well as in the manner described above.

In order to illustrate the present invention, the following examples are given, parts being by weight:--

This composition is adapted tobe colloided and extruded underpressure through an orifice to give sheets, or the like.

' Example 2 Parts Polyvinyl acetal resin. 100 Benzyl ether of ethyl glycollate 15 Pigment (as desired) This composition is adapted to be mixed either with solvent in a Werner-Pileiderer mixer, or.

without solvent in a Banbury mixer, or on hot rolls. The plastic may be comminuted and in that form is adapted for molding either by compression molding or by injection molding.

- This compositionis adapted to'be handled substantially according to the technique used with cellulose nitrate plastics and may be cake pressed and sheeted or'extruded.

This composition is particularly be mixed on hot rolls, then ground in a three-roll mill toprovide a granulated product adapted for use as a molding compound.

Example 5 Parts Polyvinyl acetal; 100 Ethyl etherot benzyl glycoilate 40 Alcohol 250 This composition gives a dope to be used for on pregnating a paper or cloth. which is subsequently to be molded.

Alcohol It will be understood that the above examples are merely illustrative, and that the present invention comprises within its scope compositions generally in which a polyvinyl acetal resin forms .the base and the ether derivatives herein described are used as modifying agents. The polyvinyl acetal resin may be varied widely with respect to the aldehyde employed to react with the polyvinyl alcohol and the extent of hydrolysis of the polyvinyl ester to form the alcohol and the extent of reaction of the aldehyde with the polyvinyl alcohol. 7

As will be obviousto those skilled in the art, the proportion of the herein described etherderivatives to be used may be varied widely. For use in plastic compositions adapted to form interlayer sheets for use in laminated glass, it is preferred that .the ether derivative comprise 40-55% of the composition but these limits may be exceeded even in the production oi laminated glass interlayers and, in the production of plasties for other purposes, will, of course, be varied to obtain the properties desired. These modifiers have the effect of conferring great toughness upon the polyvinyl acetal resins and are very advantageous in compositions for laminatedglass interlayers as they not only add toughness to the interlayer sheets but also improve the cold break tests of laminated glass using such interlayers.

Intel-layer sheets made of a plastic comprising a polyvinyl acetal resinand one of the herein described'ether derivatives as a modifier or plasticizer therefor, may be bonded directly to glass without the aid of an auxiliary adhesive or, ii .desired,- auxiliary adhesives may beemployed. 1

As many apparently widely difleren'tembodiments of this invention may be made. without departing from the spirit and scope thereof, it is to be understood that the inventioii is not limited time specific embodiments thereof excent as defined in the appended claims.

I claim: I

1. A composition a P lyvinyl acetal resin and, as a modiiien'therefor, benzyl ether of 2. A composition oompnsmg a polyvinyl formal resin and, as a modifier therefor, benzyl ether of ethyl lactate. v

3. A safety glass interlayer sheet comprising a polyvinyl acetal resin and,- as a modifier therefor, an ether derivative of an ester of a hydroxy mcnocarboxylic acid represented by the formula R1OR2COOR3, wherein R1 is a radical from thegroup consisting of aryl and aralkyl radicals containing not more than 10 carbon atoms, R: is a divalent hydrocarbon radical containing not more than 17 carbon atoms, and Ba is a monovalent radical derived from a hydroxyl compound of the class consisting of alcohols and phenols containing not more than 18 carbon atoms, and the sum of carbon atoms-of R2 and R3 does not ex-- ceed 25. 4

BARNARD M. MARKS. 

